This invention is for use in a strip packaging machine which packages articles between two superimposed continuous webs of plastic material and seals the webs together longitudinally or along the outer edges and laterally at spaced intervals to form a series of sealed and isolated compartments for the respective articles. After sealing, the web is divided into separate packages by cutting through some or all of the lateral seals. In some cases, the lateral seals may be omitted in which case the ends of the webs may be secured by retaining them between the laminations of a card on which the individual packages may be mounted.
Machines for sealing articles periodically between two continuously movable webs, using heat, pressure or adhesives or both, are well known. A typical machine is shown in U.S. Pat. No. 2,982,066. It has a pair of pressure sealing wheels on each of two parallel shafts. The wheels on one shaft are substantially tangent to the wheels on the other so that the edges of two superimposed webs may be subjected to pressure as they pass between the wheels for effecting a seal. After the longitudinally extending edge seals are made in this way, lateral seals are made between packages with suitable hot compression devices. In the machine shown in the patent, the longitudinally extending seals are continuous from package to package over the length of the web. On some occasions it is desirable to seal the outside edges and let the ends of the individual packages be free or unsealed in which case it is desirable to skip-seal, that is, to seal the outside edges along the articles being packaged but to skip or omit the seal between articles. The present invention constitutes a mechanism which may be used in a variety of packaging machines to perform skip-sealing.